The 1990s ushered in a sea change for women in rock music. Riot grrrl was booming in the Pacific Northwest, alongside grunge outfits like Hole and Babes in Toyland. Liz Phair’s “Exile in Guyville” left an indelible stamp on alternative rock, as did Shirley Manson of Garbage and Kim Deal of The Breeders and the Pixies.

Then, there was Washington D.C.-bred Mary Timony. The guitar goddess has had a prolific career, with each venture pivoting slighty from the last.

There was the math rock outfit Autoclave, signed to Dischord in the early ’90s, the supergroup Wild Flag, with Rebecca Cole of The Minders and former Sleater-Kinney members Carrie Brownstein and Janet Weiss, and the garage-pop trio Ex Hex – not to mention Timony’s numerous solo releases.

Still, the project that spanned most of the ’90s — Helium — remains at the core of Timony’s musical history. And she’s paying homage to the band with the West Coast extension of her “Mary Timony Plays Helium” tour, which stops in San Francisco on Saturday. The tour comes on the heels of last year’s “Ends With And,” a collection of demos, singles and rarities, and Matador’s reissue of the band’s catalog.

At the time of Helium’s heyday, less was more. There was more space for amateur musicians; the rougher the sound — distortion and blown-out tones on the record — the better. By the time Timony joined Helium in 1992, with Shawn Devlin on drums and Polvo bassist Ash Bowie, she shed her classical training. She’d studied at the Duke Ellington School of the Arts in her hometown, where her teachers called her a “prodigy.”
“I just wanted to play noise,” Timony said. “I didn’t want anything to sound good.”

In their two full-length albums and three EPs, Helium became known for a wide range of influences — Snoop Dogg’s “Doggystyle” played a major role in their first album, and they used medieval sounds on “The Magic City” — ambitious tunings and loud, drony guitars typical of the era.

Brownstein, of Sleater-Kinney fame and later a bandmate in Wild Flag, hit the mark when she called Timony “Mary Shelley with a guitar.” Timony’s lyricism expressed her feminism through world-making, a counter to the more explicit indictments of patriarchy and sexism of her riot grrrl contemporaries out West.

“I kind of got sick of it being talked about in a way that wasn’t accurate,” Timony told the A.V. Club last year. “So I stopped writing lyrics about that stuff. I just hated getting labeled as this crazy, angry girl.”

On 1995’s “The Dirt of Luck,” she turned mythology into pop. By the time the “The Magic City” rolled around in 1997, Timony embraced escapist themes in favor of full-on novelistic fantasy. She sang of rainbow dragons on “Leon’s Space Song” and witches and the devil elsewhere on the record.

Like any good science-fiction writer, Timony imagined worlds where freedom from gendered oppression was joined by astronauts, unicorns and vampiric sex workers. She offered sly allegories that created a new way of being for women. In her lyrics, the angry/docile or Madonna/whore binaries ceased to exist. Timony’s gray area became expansive — a realm replete with new ways of being.